Radio receiving system



July 14, 1936.

F. .1. RITTER 2,047,386

RADIO RECEIVING SYSTEM Filed 00% 5, 1954 XHAUSTZB DRY OELLD Patented July 14, 1936 UNITED STATES OFFICE .This invention is a radio receiving system, and pertains more particularly to electron tube circuits for such systems, this case being a continuation in part of application Serial No. 531,806, filed April 21, 1931, Patent No. 2,037,485, April 14, 1936. r

In radio receiving circuits of the prior art, employing electron discharge devices or vacuum tubes, it has almost universally been necessary to make use of a plurality of current sources in order to supply the filaments, plates and grids of the tubes with potential necessary for their operation. These sources have included a filament battery, a plate or B battery, and frequently, a grid or battery. Such a multiplicity of current sources has rendered the circuits cumbersome and has interfered materially with supplying the elements of the vacuum tubes satisfactorily.

Alternating current sources for supplying the elements of vacuum tubes in such systems require various forms of filters to reduce noise which results from the use of an alternating current source. These filters are quite complicated and expensive, and are subject to breakdown which renders them unsatisfactory.

The main object of the present invention is to,

simplify the system by providing an electron discharge circuit for radio receiving systems in which a single-voltage alternating current source will have direct electrical connections with each of the circuits, which respectively include the filament, the plate and the grid.

The invention will be hereinafter fully described and particularly pointed out in the claims.

In the accompanying drawing:-

. Figure 1 is a diagram of one form of radio receiving circuit embodying the invention, arranged to be supplied with alternating current from a single voltage source. Figure 2 is a detail view illustrating typical connections for a tube having a supplemental grid.

Referring to the drawing, the reference character 3 designates the usual antenna of a radio receiving circuit connected to a ground 6 through a condenser l, having a resistance shunted around it. Connected in parallel with the resistance and condenser are a tapped tuning coil 1 and a Variable condenser 8, either or both of which maybe adjusted to tune the aerial circuit to the frequency of incoming signals.

The detecting device here shown is a standard form of three-element vacuum tube 9, containing filament l0'of a cathode heater lfl plate 22 and grid l2. Current to the filament I0 is supplied from a single alternating current source 24, such as a house lighting circuit through a step-down transformer 23, preferably adapted to pp y a current of about six volts to the filament through the secondary 25. A higher voltage may be used 5 if desired.

. The current from the secondary 25 passes through the wire II, to the primary coil [4 of a radio frequency transformer T. From the coil M, a portion of the current passes through the 10 receiver l1 and conductor 21 to the plate 22.

The input or grid-filament circuit includes the aerial circuit, rheostat l3, cathode heater l0 filament 10, grid I2, Wire 18, the secondary I9 of transformer T, and wire 2|. As shown, the secondary of transformer T, is shunted by a variable condenser 20, having a resistance shunted around it. This condenser improves the sharpness of tuning but is not essential and may be omitted if desired.

The out-put or plate-filament circuit includes one side of secondary 25 of step-down trans-Q former 23, filament [0, wire II, to the primary coil M, of a radio frequency transformer T. From the coil I4, a portion of the current passes through the receiver I'l, thence through wire 21, plate 22, filament l0, and back to opposite side of secondary 25 of step-down transformer 23.

The drop in potential through the filament I0 is sufiicient to establish a difference in potential between the plate and the filament. This difference in potential is, however, increased by the drop in potential through the secondary I9, which is included in the filament circuit and has substantial resistance.

In the arrangement hereinabove described, the filament, the cathode, the plate and the grid are all supplied with current from the alternating current source through the secondary 25 of the step-down transformer 23. Ordinarily, in the system as illustrated and described, the electron discharge device will function substantially as a rectifier and a hum eliminator. If, however, an additional device is necessary to assist rectification and to completely eliminate possible hum, and to rectify the current, I make use of a combination hum eliminator and current rectifier 26. For this purpose, it has been found that a discharged dry cell containing manganese dioxide composition, is a very satisfactory hum eliminator and current rectifier, and that by employing such eliminator, clear radio signals may be received. However, this hum eliminator and current rectifier ordinarily are not essential as such and may be omitted if desired.

When a tube of the screen-grid type which employs a supplemental grid is to be used, the circuit may be arranged as shown in Fig. 2. The parts as shown in Fig. 2 correspond exactly to those of Fig.1 and are designated by the same reference characters, but a supplemental grid 29 is shown connected to the plate circuit by a lead 28. In adapting the circuit of Fig. 1 for use with a tube of this type, it is merely necessary to connect the terminal of the grid 29 in any convenient point in the plate or anode circuit, as shown.

The use of a combined radio and audio frequency transformer, such as the transformer -'I', in the manner above described renders the circuit particularly effective. may be of any standard form, and the circuit is adapted to operate satisfactorily With any of them. l

ble to use, not only in receiving circuits as illustrated, but-also amplifiers of general application, and innumerous other relations which will readilysuggest themselves .to .personsskilled in the art.

It will be observed from. the drawing that the circuits are so arranged in the apparatus as illustrated, that the total voltage of the source is applied to each of the filament, plate and grid circuits. Consequently, a predetermined .voltage source may be employed and theapparatus may. therebyloe greatly simplified over circuits in which a plurality of. sources of currentrare necessary. means directly connectingall of the elements of .the electron discharge device with a. single voltage source of low voltage alternating current,

as. herein shown and described, a decidedadvantage is gained in thatthe necessity for a separate plate circuit is avoided.v

Having thus explained the nature of.,the invention and described an operativemanner. of constructing and usingthe same, although without attempting to set forth all of the forms in which it. may be made,.or all of. theforms of its use, what. is claimed is:-

1. A radio receiving set comprising ..means.providing an antennae circuit, an electron discharge device provided With a plate, a grid, and a cathode, an input circuit therefor, means forv connecting the input circuit with the antennae circuit, means providing a single circuit including a low-voltage-source of alternating. current, to-

.gether with connections therefrom..to .the plate, grid and filament of said electron discharge device such as to utilize said single-voltage-source for complete energization thereof, a metal core transformer, said single-voltage circuit being connected in series with the .primary of said transformer and the plate, the secondary of the transformer being connected in seriesv with the inputcircuit, and means providing an output circuit including connection from said plate to said single circuit, y j v 2 A radio-receiving set comprising means providing an antennae circuit, an electron discharge device provided with a plate, a grid, a filament and a cathode heated by the filament, an input circuit therefor, means for connecting said input circuit with the antennae. circuit, means providing a single circuit including a directly connected single-voltage-source of low voltage alternating. current, connections therefrom to the plate, the grid, the. filament and the cathode of said electron discharge device such as; to utilize said single-voltage-source for complete-en- The vacuum tube 9 r Circuits embodying the invention are applica- By means of the external circuit ergization thereof, a metal core transformer, said single-voltage-source being connected in series with the primary of said transformer, the filament and the cathode, the secondary of the transformer being connected .with said input 5 circuit, and means providing an output circuit including connection from the plate to said single circuit. l 7 V 3. A radio-receiving set comprising means providing an antennae circuit,.an electron discharge 10 device provided with a plate, a grid, a filament, a cathode and a supplemental grid, an input circuit therefor, means for connecting said input circuit with the antennae circuit, means providing a single circuit including a directly connected single-voltage-source of low voltage alternating current, connections therefrom to the plate grid, the filament, the cathode and the supplemental grid of said electron discharge device such as to utilize said single-voltage-source for 20 complete energization thereof, a metal core transformer, said single-voltage-source being connect: ed in series with the primary of said transformer, the filament and the'cathode, the .secondaryof the transformer being connected with saidinput circuit, means providing an output circuit including connection from the plate to saidsingle circuit, and means for. connecting said'supplemental grid to said output circuit. A. In a radio-receiving apparatus, an electron 30; discharge device having an anode, a cathode, a grid and a filament, means providing a:single circuit including a directly. connected single voltage alternating-current-source together .with

connections therefrom to the anode, the grid and 35 V the filament of the electron discharge device such as to utilize said single voltage sourcefor complete energization thereof, anda'n amplify.- ing transformer, the primary of the transformer being connected in series withithecathode and 40 in multiple with the anode and the filament, the

secondaryv of said transformer being connected with said grid. I. 5. In a radio-receiving apparatus, an electron discharge device having aplate, a grid; 2, filai-. ment, and a cathode heated by said filament, means providing a single circuit ,includinga'directly. connected. single voltage alternating-current-source, together with 'connectio'ns therefrom to the plate, the grid,'the filament and thecathode .of said electron discharge devices'uchas to utilize said single voltage'source. oncomplete energization thereof, and an amplifying transformer, the primary of the transformeribe ing connected in series'with the filament and the cathode, and. in multiple with theplate to filament. circuit, the secondary. of said transformer being; connected with said giid;

6. In a radio-receiving apparatus, an electron discharge. device having an anode, a gridand a filament, meansproviding. a single circuit in;- cluding a directly connected single voltagealternating-current-source together: with connec-. tions therefrom to the anode, the grid. andi the 5 filament ofthe electron. discharge device'suchas 5 7 to utilize said singleivoltage source for complete energization. thereof, an. amplifying transformer, the'primary of the transformerheing connected- .in series withv the filament and in multiple with the anode to filament circuit, the secondary of 7 7. In a radio-receiving apparatus, an electron discharge device having a plate, a grid, a filament, a cathode heated by the filament, and a supplemental grid, means providing a single circuit including a directly connected single voltage a1ternating-current-source, together with connections therefrom to the plate, the grid, the filament, cathode, and the supplemental grid of said electron discharge device such as to utilize said single voltage source for complete energization thereof, an amplifying transformer, the primary of the transformer being connected in series with the filament and the cathode and in multiple with the plate to filament circuit, the secondary of the transformer being connected with said grid, and means connecting the supplemental grid with said plate to filament circuit. FREDERICK J. RITTER. 

